The 'scope of the sky

One of the four Unit Telescopes of ESO's Very Large Telescope (VLT) sits under the sky above its home, the Paranal observatory. Each UT has a main mirror 8.2 metres in diameter, making them some of the largest single-mirror telescopes in the world. Individually, each one can see objects four billion times fainter than what can be seen with the unaided eye, and when used in combination they are still more powerful. The VLT is the world's most advanced optical instrument, and is therefore well placed to make the most of the excellent viewing conditions at Paranal, which has about 300 clear nights per year.